Forum

3d projection plane

vvvv beta question
#1

Hi, i have a before-i-m-using-vvvv show wich is reborning.

Here is a video: http://www.dailymotion.com/video/x70wxv_princesse-beau-geste_creation

The projection is simple: one vp on ground projecting inside a trapezoidal box. All the compositing was done for the length from vp to box , with masks inside and its optic
All video was edited and composed for this ratio of distance and angle.
Its only flat quad projected
I would like to avoid 3d software to edit this trapezoidale box directly.
I would like to know if there is any way to recreate in vvvv a mesh simply for this and compense by camera position a new distance and angle .
The ground doesn t matter , there is 4 spaces of projection: center, sides and top

Should i use the grid or a bundle of quads ?

#2

hi karistouf
dont know if homography helps you
arrange your texture according your needs

myhomography.v4p (15.3 kB)

#3

hi DiMiX, nice to read you ;-)
hum i will surely use homography for something else. but helas not that one.
i cant focus enough texture correctly ( texture transform pin of the quad) to obtain the global image being one.

i put here some snapshot of the source itself, showing edge. but there are a lot of things working on the general image also, passing from one plane to the other.

#4

i think you will not be able to get nice multi-“keystone” correction with ONE grid, i would do it with group of 4 grids

#5

hi DiMiX, yes i have played around a bit with it.
i agree with you totally. i will try tomorow to see if i can find solution. its maybe by using keying that i could sort this… on 4 crops of the original image using at end homography on the 4 outputted textures…

#6

https://discourse.vvvv.org/t/6915

#7

hi daniel, thxs for link, but grid editor is ok only on a normal image. the project i m reborning quickly contains in its video already masks and deformations. thats the trick ;-)

#8

I can see the masks, but I don’t see the deformations. The images above all are flat, just masked for the four surfaces. So is the issue that the mask lines were assuming a certain projection geometry, correct?

Have you tested the new projector position and know there is a noticeable problem? If the projectors are a normal/long distance away, I would think you could move them quite a bit (closer/farther) without seeing much difference. Particularly if you took care to align the back wall lines, you should be able to mask spill around the outer edges. I like to try the low-tech approaches first!

Aha! Check out girlpower(slide projector) - it should work. Build your box with four quads, “project” your video on to it using the old projector position, and set your camera to the new projector position.

#9

hi mediadog, you are damned right, no deformation ;-)
flat img.

ok i take a look to it and come back ;-) nice to read you ;-)

#10

thxs mediadog, the old projector node is the better result i can have. i must wait now for reherasals with the decor to test it ;-)

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